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This testimony expanded on an earlier testimony which stated that most decelerations of mine vehicles would be much less than 10 gravities (g). Calculations were offered which indicated what was considered to be a worst case determination of deceleration forces for rubber tired underground mining vehicles. The calculation took into account the braking force, coefficient of static friction, vehicle weight, vehicle mass, and acceleration due to gravity. For dry surfaces the values of the coefficient of static friction from the literature were between 0.6 to 0.8 for slow moving, rubber tired vehicles. In this worst case scenario, therefore, it was expected that deceleration forces would be no greater than 0.6 to 0.8g. If the vehicle occupants were properly restrained, then all decelerations due to normal braking operations would not result in injuries. NIOSH reiterated the recommendation that operators and passengers be required to use full body safety restraints and ergonomically designed seats compatible with the deceleration.